Added api/webrtcsdp.h forwarding header to work around upstream projects.

webrtc/api/BUILD.gn

 # Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("../build/webrtc.gni")
 if (is_android) {
@@ skipping 56 matching lines @@
     "rtpsenderinterface.h",
     "statstypes.cc",
     "statstypes.h",
     "streamcollection.h",
     "trackmediainfomap.cc",
     "trackmediainfomap.h",
     "udptransportinterface.h",
     "umametrics.h",
     "videosourceproxy.h",
     "videotracksource.h",
+    "webrtcsdp.h",
   ]
 
   if (!build_with_chromium && is_clang) {
     # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
     suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
   }
 
   deps = [
     ":rtc_stats_api",
   ]
@@ skipping 106 matching lines @@
     deps = [
       ":libjingle_peerconnection_api",
       "../base:rtc_base_approved",
     ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 }